Faced with a spectacular and unprecedented cocktail of nasties – stagnant economy, drastic welfare reform, huge public spending cuts, rising living costs – the Welsh government has responded by appointing what it believes is the first of its kind in the UK: a cabinet minister whose primary brief is to tackle poverty.

It is a recognition that hard times are, and will be, a growing political story in the country, and an indication that it is bracing itself not just for a fresh dose of pain and social disruption, but a testing of community resilience not seen since the coalmine and steel factory closures of the 1980s.

Wales is no stranger to deepseated poverty, inequality and disadvantage. Between one in three and one in four residents live below the breadline; one in six working-age residents claim out-of-work benefits (second only to the north-east of England), and just over 9% of these are on incapacity benefits.

The consequences of this hammer blow on those least able to cope will be profound, says Lewis. At government level, tackling poverty can no longer be, in administrative terms, a specialist programme attached to a junior ministerial portfolio, but must be placed at the core of policymaking. "The first minister, when he appointed me, clearly felt that the pressures that Welsh families were going to be put under in the next couple of years more than merited that central [Welsh] government priority."His aim is to ensure that the government machine "turns to face the people caught up in the poverty statistics", says Lewis. "This isn't a fringe group at the edge of society; in Wales we are talking about one in three of the population. That's the scale of the problem."

The Welsh government's analysis of the financial impact of welfare reform makes for stark reading. About 42,000 claimants will lose entitlement to disability living allowance by 2018, a collective annual income cut of £122m. Time limits to employment and support allowance will lead to 56,000 people losing up to £89 a week. Around £40m a year will disappear as a result of the bedroom tax. The less high-profile cuts deliver bigger numbers: cuts to tax credits and the 1% cap on the uprating of working-age benefits, for example, will see hundreds of millions drained from the economy over the next couple of years.

Notwithstanding the possibility that the coalition's welfare reform will push substantially more people into work – unlikely as that may be, says Lewis – the potential consequences of these reforms will be poorer public health, debt problems, overcrowding and increased demand for crisis help. Social care services and the NHS will come under increased pressure, while educational attainment may dip, according to the Welsh government analysis.

"To my mind, we are very much in danger of not just hurting individuals but destabilising whole communities," says Lewis.

He is already seeing the disruptive consequences of the bedroom tax in his own constituency, Merthyr Tydfil and Rhymney, in south Wales. "I've met several constituents of mine who are being hit by the bedroom tax because their children have grown up and left or gone to college or university. They are not pensioners yet and now they are in a situation where they can't afford a roof over their head.

"Those people – in that age group particularly – are quite often the people who make a community tick. They are steady, settled; they are people who look after their gardens, volunteer [locally]. They are the people who step up in a community, now they have perhaps a little more time on their hands to do those things that make a community a good place to live, and these are the very people that are being told, 'You have to go now'.

"This is just beginning to hit people as a reality now. Over the next six months, particularly in the runup to Christmas, when people are really beginning to feel the pinch in terms of their family finances and so on, we will begin to see an unravelling of people's ability to cope. I don't think communities have seen anything quite like this since the poll tax."

Lewis rails against what he sees as a brazenly ideological attempt by the coalition government in Whitehall to "take advantage of a good crisis" to foist an "almost American-style social security setup" on the UK – a move he has called a "social atrocity".

But he is also aware that while the Welsh government will be judged on its ability to mitigate the effects of austerity and to pick up the pieces, it has little room for manoeuvre. There are no magic wands. This year the Welsh government has borne the £23m cost of meeting cuts to council tax benefit ("a do-able piece of mitigation", says Lewis), but there are no guarantees that the subsidy will continue next year. The Welsh assembly itself will lose £3bn from its £14bn budget over the next two years.

Lewis's aim is to co-ordinate government spending across departments, joining up policy and short-circuiting silos so that tackling poverty, whether in education, health or local government, is central. There will be targets and milestones (including a reaffirmed commitment to meet the 2020 child poverty targets), and "focused conversations" with colleagues, says Lewis. All public expenditure will be biased towards the individuals and communities worst hit by austerity, a process Lewis calls "programme-bending".

But Wales cannot afford heroic, big-ticket interventions. There will be, he admits, some "difficult decisions and conversations to be had". Any cash will be focused on initiatives and organisations that help individuals and communities become more resilient. That means support for advice agencies ("I'm not going to see Welsh advice agencies fall off a cliff in a way that they may do in England," he says), credit unions (though the Welsh credit union movement is "still quite young", he cautions), and partnerships with the voluntary sector.

You sense that some of this sticks in the craw for Lewis. The growth of charity foodbanks, he admits "is a regrettable thing to have to be involved with" and "leaves a bitter taste in the mouth". But he embraces it, nonetheless. "You can't afford to be prissy or ideological about this; they [foodbanks] are fulfilling a need and we want to work alongside them."

The fallback on community resilience - or "self-defence" as he calls it – can sound a bit big-society-ish, he admits. But it also goes with "the grain of Welsh community-mindedness", tapping into long traditions forged through adversity. You sense a country settling in for a long, hard, attritional conflict against an alien oppressor.

There will be " crashes" ahead as a result of austerity, says Lewis, and the social consequences are difficult to predict. But his is not a counsel of despair. He senses "a huge amount of resilience out there", and professes optimism that families and communities will step up. He says: "They will rally round in ways we haven't seen since the miners strike."